Photographic film forming image transfer composition



July 15, 1952 5.1-1. LAND PHOTOGRAPHIC FILM FORMING IMAGE TRANSFER COMPOSITION Filed Feb. 17, 1947 Patented July 15, 1952 PHOTOGRAPHIC FILM FORMING IMAGE TRANSFER COMPOSITION Edwin H. Land, Cambridge, Mass., assignor to Polaroid Corporation, Cambridge, Mass., a corporation of Delaware 7 Application February 17, 1947, Serial No. 728,983 13 Claims. 95- -88) This invention relates to photography, and more particularly to processing agents or compositions useful in the processing of a photosensitive emulsion.'

This application is a continuation-in-part of my copending application Serial No. 576,254, filed February 5, 1945, for Photographic Process, Apparatus and Product (now abandoned).

One object of the present invention is to provide a novel liquid processing agent or composition capable, when spread over a photosensitive emulsion, of developing said emulsion and forming adjacent said emulsion a substantially solid film.

Another object of the. present invention is to provide a novel film-forming composition of the above character which is capable, when spread over a photosensitive emulsion, of providing in the solid film obtained'therefrom or in or on a base associated. with said film a positive image of the subject matter to which said photosensitiv emulsion-was exposed.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the com position'of matter possessing the features, properties and the relation of components which are exemplified in the following detailed disclosure, and the scope of the application of which will be indicated in the claims.

For' a fuller understanding of the nature and which comprises part of the novel composite product of the present invention;

Fig. 3 is a perspective view of the composite product;

Fig. 4 is a sectional view taken substantially along line 44 of Fig. 3;

Fig. 5 is an enlarged, fragmentary, sectional view in perspective illustrating another form of composite product embodying the liquid. composition of the invention; and

Fig. 6 is a longitudinal sectional view showing still another composite productgembodying the liquid composition of the invention.

The present invention comprehends as a novel photographic processing agent a film-forming liquid composition so composed that when the same is applied in a predetermined relatively thin layer over a photosensitive silver halide emulsion, the liquid content thereof permeates said emulsion to subject the same to a predetermined processing and, with the evaporation and/or absorption of the liquid content of the composition, the film-forming ingredient thereof provides .a solid film throughout the area of application of the composition. The composition is particularly adaptedfor use in a camera for suj ectinga photosensitive silver halide emulsion to a desired processing shortly after exposure thereof. By distributing the composition between the exposed film and another sheet of material, it is possible to confine all of the liquid to the lamination comprising said film and sheet material, the amount of liquid in the composition being such that there is no appreciable wetting of the outer surfaces of the lamination so obtained. The liquid composition is thus ideally suited to carrying out what istantamount to a dry Processing of a photosen- 1 plex with silver halide, and a film-forming ma terial. Upon application of the composition to a silver halide emulsion,,the developer in the composition acts to develop any latent image in the emulsion and the silver halide solvent forms a soluble complex with the unexposed silver halide during the development, which complex may be transported from the emulsion to another stratum of material to form therein a positive imagecomprising silver of the subject matter of the developed image in the emulsion. The film-forming material, which is preferably a high molecular weight polymer, imparts to the compositiona predetermined high viscosity and is of such character as to retain its viscosity-imparting and film-forming properties in an aqueousv alkaline solution so that the processing agent, once its the alkali-inert and Water-soluble cellulose derivatives such as sodium carboxy-methyl cellulose, and hydroxyethyl cellulose, and other alkali-inert and Water-soluble polymers such as the sodium salts of polymethacrylic acid and polyacrylic acid.

Examples of developers useful in the foregoing composition are hydroquinone, monomethyl-paminophenol sulfate (Elon, Metol), a mixture of hydroquinone and monomethyl-p-aminophenol ulfate, p-aminophenol hydrochloride (Kodelon), p-hydroxyphenylaminoacetic acid ..(Athenon, Glycin), p-phenylenediamine, o-phenylenedia amiriapyrocatechin (pyrocatechol, catechol), diaminophenol dihydrochloride (Amidol) diaminophenol hydrochloride ('Acrol), pyrogallol, chlorohydroquinone, dichlorohydroquinone, tetrachlorohydroquinone, bromohydroquinone, toluhydroduinone, xylohydroquinone, o-aminophenol, 2 amino-5 diethylaminotoluene hydrochloride, ptertiarybutyl catechol, hydroquinone disulfonic acid (potassium salt), 2,5-ditertiarybutyl hydroquinone, and p-aminodiethylaniline.

Examples of materials which may be used in the composition for, the purpose of forming a soluble silver complex with the undeveloped silver halide of the photosensitive layer are sodium thiosulfate, sodium thiocyanate, ammonium thiosulfate, ammonia and sodium cyanide. Where a compound is toXic such as sodium cyanide, precautions should be taken in the use thereof.

Examples of suitable alkalis are sodium hydroxide, potassium hydroxide, sodium carbonate, borax, sodium metaborate, or trisodium phosphate.

The composition may also contain sodiumsulfite which acts in part as a preservative and may also function as a silver halide solvent. Citric acid may also be added to the composition to provide abuffer.

t The spreading of the processing composition in a substantially uniform layer over, a predetermined area of a photosensitive emulsion In of a photographic film l2 may be accomplished by introducing between said emulsion and a suitable base or image-carrying layer (Fig. l) a predeterminedquantity of said processing composition l6, said composition being originally disposed adjacent one edge of said predetermined area in a mass extending parallel to said edge over a length substantially coextensive with said edge. After the introduction, image-carrying layer [4 andfilm l2 aresqueezed together as, forexample, by being advanced between a pair of pressureapplying elements suchas squeegee roller i8 or plates to cause the composition to be spread as a liquid layer 20 between the inner surfaces of said image-carrying layerand emulsion Ni, layer 20, upon the drying and/or absorption of the liquid content thereof, forming a solid layer of plastic.

.The thickness of layer 20 will be subject to control.

by variations in the pressure applied by the pressureeapplying elements to the lamination comprising. image-carrying layer I4 and film [2 as said lamination is drawn through said pressure-applying elements. The thicknessof layer 20 will also 4 permeability of the surfaces of the layers of material in contact with the composition.

The presence of the plastic in the composition insures that the surfaces of emulsion I 0 and image-carrying layer l4 are immediately Wetted with the composition as the layer, 20 thereof is formed. The plastic additionally erves as a'spacer between layers [0 and I4, holding them far enough apart to provide an adequately large reservoir and sink for the ions and molecules that must enter and leave it while keeping the surfaces near enough together so'that the image-forming particles precipitated in it are made up from dissolved components that have arrived along a very short radius of diffusion. Film l2 and layer I4, as they emerge from the pressure-applying elements, are bonded together by means of layer'20 just tightly enough so that they do not separate spontaneously during the time of processing and yet when they have imbibed most of the liquidfrom said layer 20 they can be peeled apart. a g

It is to be understood that by a suitable selection of the film-forming material in composition [5, the solid film or layer 20 which is formed therefrom may be caused to adhere to either the photosensitive emulsion l0 or the surface of image-carrying layer l4=whenand if the latter are peeled apart subsequent to the processing. 'For example, if the film-forming material is the plastic sodium carboxymethyl cellulose and'base I4 is 'a paper such as a baryta paper, the'solid film of sodium carboxymethyl cellulose, when formed, will have a greater affinity for the surface of layer M than for the gelatin of emulsion Ill, provided, of course, that the latter is an ordinary emulsion comprising the usual partially but not fully hardened gelatin and the liquid in the composition does not complete the hardening thereof. As a result, the solid plastic film 20, when formed, will adhereto the image-carrying layer when the'latter is stripped from film I2. In general, for example, the sodium carboxymethyl cellulose film will adhere to the harder of two layers of gelatin between which it is spread. Accordingly, if the surface of any image-carrying layer is provided with a thin coating of a substantially fully hardened gelatin, the film of sodium carboxymethyl cellulose will adhere to said image-carrying layer in preference to the relatively softer gelatin layer of the photosensitive emulsion.

It is, of course, possible to increase the adhesion between the solid film 20 and either emulsion layer H] or the surface of layer I4 by surfacing one of said layers with a coating of other materials which have a desired high affinity for the solid plastic film. For example, by subcoating layer M with a coating of the same high molecular weight polymer which is the film-forming material in the processing agent, the solid layer 20, when formed, will be caused to strongly adhere to layer 14.

In the event the image-carrying layer i4 is surfaced with a subcoating of the same material as the film-forming material in the reagent or where the film-forming material is sodium carboxymethyl cellulose and the base is a baryta paper, the image-forming component is ordinarily precipitated in part in said subcoating'or the surface stratum of paper so that the positive image is formed in part in the plastic film 20 and in part in or on layer l4 and/or said subcoating. Control of the stratum wherein the positive image components are predominantly precipitated may'also be achieved by the suitable use of material which attracts and aggregates the'image-forming ionsas by.distrib uting' such material in the stratum ;wherein the image isto be formed. Moreover, it a plurality appreciable extent the stratum within .which the image-forming ions are ultimately precipitated to give the positive image. For example,

'by having the surface stratum of image-carrying layer It formed of a partiallyhardened gelatin and by employing hydroxyethyl" cellulose as the film-forming material in composition I 6, the

image-forming silver ions maybe caused to almost entirely precipitate in the stratum of gelat v Although image carrying layer It is preferably a baryta paper, it may be formed of such ethyl cellulose, or their-derivatives such as' -sodium carboxymethyl cellulose, aluminum parother papers, proteins such as gelatin and cartures of these materials where the latter are compatible. If said layer is formed of a transparent material, it may be, provided with a white opaque base or in the alternative the normally translparent material of said, layer may be rendered opaque by theincorporation of a suitable pi .ment such, forexample, as titanium dioxide.

v'lI-hotosensitive emulsion l preferably comprises a silver halide ora mixture of silver halides or a silver mixed jhalide in a suitable carrier, pref erably gelatin. Suitable materials for providing the photosensitive layers forthe practice of the invention are the, commercially available photographic films and papers such as EastmanlKodak able quantities to impart to the composition a viscosity in excess of 1,-000 centipoises at a temperature of approximately 24 C. and preferably of the order of 1,000 to 200,000 centipoises at said temperature. These high viscosities areimportant for any'commercial application of .said composition in view of the order of nonuniformityof commercially available materials and pressure-applying means to be used in'connection therewith.

It is to be understood that thixotropic effects may cause an apparent change in viscosity in the composition as *when the composition, after being confined in a space of predetermined configuration without appreciable disturbance for a relatively long period of time, is a itated.

Examples of suitable film-forming compositions capable, when spread between a photosensitive emulsion and an image-carrying layer, of

developing a latent image in said emulsion and of forming a positive image in a stratum of the lamination. other than said photosensitive emulsion are given below, but it is to be expressly understood that they are merely illustrative.

Example-1 1.5 Sodiumsulfite i 78 Sodiumhhydroxide, '.'.L 74.6 Sodium;:.thiosulfate 14.5

boxymethyl cellulose and hydroxyethylicellulose,

'bohydr'ates such as gums and starch, and mix- Citric acid Hydroquinone "The" 'sodium' carboxymethyl cellulose, for example Ethe commercially available .1 Hercu s 1 mediumwiscosity .type,-.f:isdissolved inthe water .ina'mixer at roomtemp'erature and the solution .ismixed :th'ereim for. approximately one hour. 'Ther-ieaftenithe sodium .gsulfite, the sodium hy- .droxide,the'-.sodium thiosulfate and the, citric -acid are addedzto the solution;:t-he addition being other materials as for example, regenerated cellulose, a poly'liydroxy alkane suchas polyvinyl alcohol, sodium alginate, cellulose ethers such as effected inert-j atmospheraior example of nitrogen. Upon dissolution of these materials,

the hydroquinone is ,addedand the solution is ,Iurther mixed for an hour at approximately room temperature-in --a nonox-idizingatmosphere of ;nitrogen.* This "composition, when} spread be-' itween-g, photograph-ically-exposed photosensitive I emulsion such; for example, --as the emulsion of Eastmanjiodak-Contrast Process Ortho film and baryta'paper ini a layer, for; example, of a thickness between' ;0,02"'1and: .003", is capable of pro- ,ducinga-positive image of the subject matter of the latent-image in said'emulsion inapproximately'one minute: At the end of approximately one minute, the --photosensitive film and the baryta paper are stripped apart, leaving a finished "positive image of good" contrastlon' .th'e baryta paper. It the liquid compositiohis spread in a $hi0kl$ approximating the: foregoing thickness, thereis no appreciable wetting of theouter surfaces of the photosensitive film .or the. baryta paper during this'processing', the liquid being present in sufliciently. smalliquantities to be substantially completely, ,.absorbed by the, sheets. Faster film such, foriexample as Eastman Kodak vqricilriomeorjSuperfXX. may be used, but it. is preferable, .whenthesej films are used, in order 4 ;to.,a'ssure the formation of; .sub'st'antially; black image's, to increase theIsodium thiojsulfate content of the composition as, for example, by doubling the amount thereoi specified above. A good quality image car-raise be obtained when using v these faster films without-increasing the sodium thiosulfatecentent by spreading'on the imagecarrying-layer orbaryta paper a thin coating of the following mixture of materials:

40%;aqueous solution of neutral lead 15% aqueoussolution of ascorbic ,acid cc 36 Example 2 In the-composition of Example 1, any one of ,the following developers maybe substitutedin .65. substantially the same quantity as the hydro- .q nqn Peaniinophenol hydrochloride; bromohydroquinone; chlorohydroquinone; diaminophenol hydrochloride; diaminophenol dihydrochloride;

toluhydroquinone; monomethyl-p-aminophenol (I5. fourths phydroxvphenylaminoacetic acid.

An aqueous solution of Hercules OIPYDOW' carboxymethyl cellulose, sodium salt",medium viscosity, consisting of 200 g. of the t i latter compound in 1000 cc. of water g 50 Sodium hydroxide, solution cc 112 The foregoing materials may be mixed in the same way as" the materials'of Example 1,"or in the alternative; the sodium sulfite, hydroquinone, "and sodium thiosulfate are dissolved in the water, and the sodium carboxymethyl cellulose solution is then added and thoroughly mixed therewith. 'Thesolution thus obtained is cooled to a temperature between 65- to 75. F. and thereafter the sodium hydroxide solution is added thereto.

I Example 4 i f Water- Y cc 1500 .Hydroquinone g 28 Sodium sulfite g 200 Metol g 15.5 Sodium thiosulfate "g-.. '100 .A queous solutionof medium 7 scosit'y sodiumcarboxymethyl cellulose consisting 7 of 200 g-. of the latter compound in 1000 cc. a of water g 1000 *Sodium hydroxide-"i g 56 j J 7. Example 5 7 Water cc 2400 Sodium sulfite I '90 Sodium hydroxide g-- 87.5 Hydroxyethyl cellulose g 21.31 Sodium thiosulfate g 5 Hydroquinone g 9 Example 6 2 5.00 grams of' hydroxyethyl' cellulose; for example the product sold by Carbide' and Carbon Chemical Corp; and identified 'as hydroxyethyl cellulose (7.1.2cps), are'dissolvedin'1000 cc. of water and. 200 cc. of this solution aremixed with 500 cc. of a solution comprising thefollowing:

Sodium sulfite g 180 Sodium hydroxide g 37.5

Hydroquinone -1 g 180 Sodium, thiosulfate g 50 Water to make c0 1500 Example 7 V Grams Sodium sulfite 78 Sodiumhydroxide 110 Sodium thiosulf ate Citric acid 39 Hydroquinone 52 If a relatively white and nontransparent film is to be formed by the liquid composition, there may be incorporated in any one of the foregoing compositions a suitable pigment such as titanium dioxideor mixtures of titanium dioxide and magnesium oxide or magnesium carbonate. The ad- 'dition of titanium dioxide equivalent to from 10% .of retaining the processing composition therewithin for relatively long periods of time-Without vapor loss or oxidation.

The, container is preferably constructed so as to be mounted, adjacent the area which the contents thereof are to process, for ready release of its contents throughout said, area. To this end it is preferably elongated in shape, the length thereof being equal at least to the width of the thereof.

,One example of; asuitable container ofthis type is formed from a single multilayershe'et of material 30 (Fig. 2) comprising three layers 30a, 30b, and 300. i Layer 30a, which provides themternal surface layerof the container, is formed of a material which is chemically inert to the processing agent and 'whichis impervious to. the liquid of the agent. One class of materials suitable for this purpose is the polyvinyl acetals; and

of the acetals polyvinyl butyral. is a preferred species, A compositioncomprising 60% to: 72% by weight of polyvinyl butyral, 10% to 23% by weight of A2" nitrocellulose, and approximately 5% by weight of dibutyl sebacate is particularly satisfactory as inner coating 30a. Layer 30?) contiguous to'layer 30a. is preferably impervious to I the vapor of the processing agent and is formed,

for example, of a metallic foil, such as lead or use of thinner layers 30a and 30b.

The container dll (Fig. 3) is'p'referably formed by taking the single sheet of material 30 and folding the same medially as shown in Fig. 2 and thereafter securing the end marginal portions 32 and the longitudinal marginal portions '34 of the two fold faces to one another, providing a central space or cavity 35 (Fig. 4) for, containing the processing agent.

To fill the container, it is possible, for example, to adhere together the opposite longitudinally extending marginal portions 34 and the end marginal portions 32 at one end only of 'the container, the container being thereafter filled through the otherend. z 5

It is desirable that the container be capable of releasing its contents throughout substantially its entire length so that by mounting-the container with its longitudinal edge 34 adjacent the image area opposite oneedge thereof; the contents may be uniformly spread throughout substantially the entire width of the image area. To this end, the longitudinal seal between marginal portions 34 is such that upon application of a predetermined compressive force to the Walls of the container there may be created within the container a sufficient hydraulic pressure to separate the marginal portions 34 throughout substantially their entire length. To insure this result, the bond securing together said marginal portions 34 is somewhat weaker than the bond which secures togetherl end marginal;p.ortions -32. For example, the end portions may the secured by pressing the two polyvinyl butyralinnergsurfaces together and applying heat thereto while .aqsealin-g strip 36 may be inserted between the longitudinal marginal portions, which sealing strip is adapted to adhere the the inner layers of polyvinyl butyral with a lesser afiinity than "said layers adhere to oneanother -a direct polyvinyl butyral -to polyvinyl butyral bond- Strip-36 may :befor-medof .a material such as ethyl cellulosesor a mixture of ethyl cellulose :and :paraffin.

, One or more containers 4:0 :may :be associated with the; sheet material to provide a sheet-like product capable of subjecting one or more areas of a phQ iQSensitive film to :a predetermined proccomposite sheet-like structure thus obtained is capable, when pressed into engagement with the surface of a photosensitive emulsion, of subjecting a predetermined area of said emulsion to a desired processing, said predetermined area being a portion at least-of that area of the emulsion which is in contact with the surface of sheet 42 between containers 40. The processing may be carried out by applying a su flicient compressive force to container 140 to cause the separation of the sealed portions 34 thereof and by continuing the application of this compressive force in sulficient magnitude to effect the spreading of the released liquidthroughout the area of contact of sheet 42 and the photosensitive emulsion. This provides adjacent the photosensitive emulsion a relatively thin uniform layer of the processing .agent. The latter may act to develop and fix a latent image in the photosensitive emulsion and itymay also serve to provide layer-42 with a thin,

solid film of plastic. The plastic film may serve as an image-receiving layer or may cooperate with layer'42 to so function.

The sheet-like product-comprising layer 42 may comprise a part of -aycomposite photographic film (Fig. 6),, which includes as a part of its unitary structure a transparent film base -46, a photosensitive emulsion 48 mounted on said film base -and=one .of image-carrying-layers 42. Containers 40 are thus located between saidphotosensitive emulsion and said image-carrying layer and are capable of discharging their fluid content throughoutAthe interface area .of said layers, This composite photographic film may 'be provided as a roll film, in the form of .a film pack comprising .a plurality of interconnected frames, or insingleframes.

When the film-forming .agent carried by container-4'0 is released therefrom and spread between a photosensitive emulsion .such .as emulsion 48 andan image-carrying layer such as layer 42, the two layers in contact with the thin layer of compositionktherebetween prevent the latter from oxidizing. It becomes possible, therefore,

to employ higher concentrations of materials subject to oxidation in the processing agent when used in this manner than can be employed in compositions .when used, .for example, in the '10 ordinary developer bath which have :a substantial surface thereof exposed .to oxygen when in use. 7

Moreover, the presence of the film-formingmaterial in 'the liquid composition carried (by the container 40, whereby the viscosity .of the latter is substantially increased, acts to insure an un- ..sealing of the longitudinal edge '34 @of the .contai-ner throughout substantially the entire length thereof, whensuflicient compressive .-force is applied to the container =faces, thereby insuring the provision of a mass of the composition throughout said length free for spreading over the desired area.

While it is preferable to spread the liquid composition over the photosensitive emulsion by introducing the same between said emulsion and another sheet material and squeezing together said sheets, the spreading may also-be accomplished without the use of said othersheet mate- .rial as, tor example, by means of an applicator roll which engages and spreads the composition over the photosensitive emulsionand which pref a ferablyis so surfaced as/ not to adhere to the com- ;position. In the latter eventthe composition may be of the type adapted to form a white, opaque .solid :film when dry and may contain a sufficient quantityof silver halide solvent to cause the formation of a positive image insilver inthe white layer, which image is visible from the surface .of said White layer remote from the ,photosensitive layer. :Ihe white layer serves :as .an opaque barrier :obstructing the negative from view and provides the highlight portions of the positive image. i

The term' over said emulsion s used herein .is to be understood to include the application of the liquid composition to a photosensitive emulsion so that the same is direct contact with the surface of the emulsion and-also to :include the application of the composition so that the same is spaced a slight distance from the emulsion, as by an intervenin coating, which :c'oating is permeable to the liquid of the composition .so that the liquid may readily permeate tromrthe point of original application :to the photosensitive layer.

Since certain changes may be made the above composition of matter without "departing from the scope .of the invention herein involved, it :is :intended that all matter contained in the above description or shown ins-the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

Whatisclaimedis': i 1

1. Asa new composition, a viscous film-forming processing agent comprising, in aqueous *so-, lution, hydroquinone, sodium thiosulfate, an alqkali, and sodium carboxymethyl-cellulose inssufii- 'cientouantityto impart to said solution :a *vis- .cosity of theorder'of 1-,000 to 20Q,000 centipoises at aatemperature-of approximately 2d C.

2. A photographic processing composition for :forming transfer prints of latent images contained in silver halide-emulsions, which composition comprises a silver halide developer, a solvent including water forsaid developer, an alkali, a Water-soluble silver halide solvent and a watersoluble, film-forming high molecular weight polymer, said polymer forming a solid film .upon removal of the liquid content of said composition and being in the composition in sufficient quantity to impart thereto a viscosity of the order of 1,0001to 200,000c'entipoises at 24 C., said polymer being water-soluble lhydroxye'th'yl cellulose and line solution, said Composition, when spread ina layer of the order of several thousandths of an inch in thickness between a photosensitivesilver halide emulsion containing a latent image and a print-receiving layer, being capable of forming a transfer print of said latent image, of maintaining said emulsion and print-receiving layer in spaced laminated relationship during the formation of the print and of forming a solid film throughout the spread area when the liquidcontent of the composition has been absorbed and evaporated therefrom. f

3. A photographic processing composition for forming transfer prints of latent images contained in silver halide emulsions, which composition comprises a silver halidedeveloper, a solventincluding water for said developer, alkali metal hydroxide, alkali metal thiosulfate, and a watersoluble, film-forming high molecular weight polymer, said polymer forming a, solid film upon removal of the liquid content of said composition and being in the composition in sufiicient quantity to impart thereto a viscosity of the order of 1,000 to 200,000 centipoises at 24 C., said polymer being a water-soluble hydroxyeth'yl cellulose and retaining its viscosity-imparting and film-forming properties for prolonged periods in the alkaline solution, said composition, when spread in a layer of the order of several thousandths of an inch in thickness between a photosensitive silver halide emulsion containing a latent image'and a print-receiving layer, being capable of forming a transfer print of said latent image, of maintaining said emulsion and print-receiving layer in spaced laminated relationship during the formation of'the print and of forming a solid film thruoghout the spread area when the liquid content of the composition has been absorbed'and evaporated therefrom.

4. The composition of claim 1 wherein the alkali is sodium hydroxide.

5. As a new composition, a viscous film-forming processing agent comprising in aqueous solution a silver halide developer, an alkali metal thiosulfate, an alkali metal hydroxide and a carboxymethyl cellulose of an alkali metal, said carboxymethyl cellulose being in sufficient quantity to impart to said solution a. viscosity in excess of 1,000 centipoises at a temperature of approximately 24 C.

g6. Alphotographic processing composition for forming transfer prints of latent images contained in silver halide emulsions, which composition comprisesa silver halide developer, a solvent including water for said developer, an alkali, a water-soluble silver halide solvent, ande. watersoluble, film-forming, high molecular-weight polymer, said polymer forming a solid film upon removal of the liquid content of said composition and being in the composition in sufficient quantity to impart thereto a, viscosity of the order of 1,000 to 200,000 centipoises at 24 0., said polymer bein a water-soluble carboxymethyl cellulose and retaining its viscosity-imparting and film-forming properties for'prolonged'periods inthe alkaline solution, said composition, when spread in a layerof the order of several thousandths of an inch in thickness between a photosensitive silver halide emulsion containing a latent image'anda print-receiving layer, being capable of forming a transfer print of said latent 'carboxymethyl cellulose.

1 2 during the formation of the print and of forming a solidfilm'throughout the spread area when the liquid content of the composition has been absorbed and evaporated therefrom. V

'1. The composition of claim 6 wherein the water-soluble carboxymethyl cellulose is sodium 8. A photographic processing composition for forming transfer prints of latent images contained in silver halide emulsions, which composition' comprises a silver halide developer, a solvent including water for said developer, analkali, aWater-soluble silver halide solvent, and a water-soluble, film-forming, high molecular weightpolymer, said polymer forming a solid film upon removal of the liquid content of said composition and being in the composition in sufficient quantity to impart thereto a viscosity of theorder of 1,000 to 200,000 centipoises .at 24 C., said polymer being a water-soluble salt of polymethacrylic acidand retaining its viscosity-impartperiods in the alkaline solution, said composition,

when spread in a layer of the order of several thousandths of an inch in thickness between a photosensitive silver halide emulsion containing a latent'image and a print-receiving layer, being capable of forming a transfer print of said latent image, of maintaining said emulsion and print-receiving layer in spaced laminated relationship during the formation of the print and of forming a solid film throughout th spread area when-the liquid content of the composition has been absorbed and evaporated therefrom.

-9. A photographic processing composition for forming transfer prints of latent images contained in silver halide emulsions, which composition comprises a silver halide developer, a solvent including water for said developer, alkali metal hydroxide, alkali metal thiosulfate, and a water- 'soluble, film-forming, high molecular weight polymer, said polymer forming a solid film upon removal of the liquid content of said composition and being in the composition in sumcient quantity to impart thereto a viscosity of the order of 1,000 to 200,000 centipoises at 24 C., said polymer being sodium carboxymethyl cellulose and retaining its viscosity-imparting and filmformin properties for prolonged periods in the alkaline solution, said composition, when spread in a layer of the order of several thousandths of an inch in thickness between a photosensitive silver halide emulsion containing a latent image and a print-receiving layer, being capable of forming a transfer print of said latent image, of maintaining said emulsion and print-receiving layer in spaced laminated relationship during the formation of the print and of forming a-solid film throughout the spread area when the liquid conevaporated therefrom. v

10. A photographicprocessing compositionfor forming transfer prints of latent images contained in silver halide emulsions, which composition comprises a silver halide developer, a solvent including water for said developer, alkali metal hydroxide, alkali metal thiosulfate, and a' water-soluble, film-forming, high molecular weight polymer, said polymer forming a solid film upon removal of the liquid content of said composition and being in the composition in sufiicientquantity to impart thereto a viscosity tent of the composition has been absorbed and v of the order of 1,000 to 200,000 centipoises at 24f image, of maintaining said emulsion andprint- I C., said polymer-being the sodium'salt of poly,- methacrylic acid and retaining its viscosity-im- 13 parting and film-forming properties for prolonged periods in the alkaline solution, said composition, when spread in a layer of the order of several thousandths of an inch in thickness between a photosensitive silver halide emulsion containing a latent image and a print-receiving layer, being capable of forming a transfer print of said latent image, of maintaining said emulsion and print-receivinglayer in spaced laminated relationship during the formation of the print and of forming a solid film throughout the spread area when the liquid content of the composition has been absorbed and evaporated therefrom.

11. A photographic processing liquid composition for forming transfer prints of latent images contained in silver halide emulsions, which composition comprises a silver halide developer, a solvent including water for said developer, an alkali, a water-soluble, silver halide solvent, and a water-soluble, film-forming, high molecular weight polymer from the class consisting of the carboxymethyl and hydroxyethyl celluloses and the salts of polyacrylic and polymethacrylic acids, said polymer being in the composition in sufiicient quantity to impart thereto a viscosity in excess of 1,000 centipoises at a temperature of approximately 24 C. and retaining its ,viscosity-imparting and film-forming properties in the alkaline composition.

12. A photographic processing composition for forming transfer prints of latent images contained in silver halide emulsions, which composition comprises a silver halide developer, a solvent including water for said developer, an alkali, a water-soluble silver halide solvent, and and a water-soluble, film-forming, high molecular weight polymer, said polymer forming a solid film upon removal of the liquid content of said composition and being in the composition in suflicient quantity to impart thereto a viscosity 01' the order of 1,000 to 200,000 centipoises at 24 C., said polymer being a salt of polyacrylic acid and retaining its viscosity-imparting and film-forming properties for prolonged periods in the alkaline solution, said composition, when spread in a layer of the order of several thousandths of an inch in thickness between a photosensitive silver halide einulsion containing a latent image and a print-receiving layer, being capable of forming a transfer print of said latent image, of maintaining said emulsion and printreceiving layer in spaced laminated relationship during the formation of the print and of forming a solid film throughout the spread area when the liquid content of the composition has been absorbed and evaporated therefrom.

13'. A photographic processing composition for forming transfer prints of latent images contained in silver halide emulsions, which composition comprises a silver halide developer, a. solvent including water for said developer, alkali metal hydroxide, alkali metal thiosulfate, and a water soluble, film-forming, high molecular weight polymer, said polymer forming a solid film upon removal of the liquid content of said composition and being in the composition in sufiicient quantity to impart thereto a viscosity of the 7 order of 1,000 to 200,000 centipoises at 24 C., said polymer being the sodium salt of polyacrylic acid and retaining its viscosity-imparting and film-forming properties for prolonged periods in the alkaline solution, said composition, when spread in a layer of the order of several thousandths of an inch in thickness between a photosensitive silver halide emulsion containing 'a latent image and a print-receiving layer, being capable of forming a transfer print of said latent image, of maintaining said emulsion and printreceiving layer in spaced laminated relationship during the formation of the print and of forming a solid film throughout the spread area when the liquid content of the composition has been absorbed and evaporated therefrom.

EDWIN H. LAND.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS OTHER REFERENCES Mees, The Theory of the Photographic Process, published by The MacMillan Company, New,

York, 1942, page 337. 

11. A PHOTOGRAPHIC PROCESSING LIQUID COMPOSITION FOR FORMING TRANSFER PRINTS OF LATENT IMAGES CONTAINED IN SILVER HALIDE EMULSIONS, WHICH COMPOSITION COMPRISES A SILVER HALIDE DEVELOPER, A SOLVENT INCLUDING WATER FOR SAID DEVELOPER, AN ALKALI, A WATER-SOLUBLE, SILVER HALIDE SOLVENT, AND A WATER-SOLUBLE, FILM-FORMING, HIGH MOLECULAR WEIGHT POLYMER FROM THE CLASS CONSISTING OF THE CARBOXYMETHYL AND HYDROXYETHYL CELLULOSES AND THE SLATS OF POLYACRYLIC AND POLYMETHACRYLIC ACIDS, SAID POLYMER BEING IN THE COMPOSITION IN SUFFICIENT QUANTITY TO IMPART THERETO A VISCOSITY IN EXCESS OF 1,000 CENTIPOISES AT A TEMPERATURE OF APPROXIMATELY 24* C. AND RETAINING ITS VISCOSITY-IMPARTING AND FILM-FORMING PROPERTIES IN THE ALKALINE COMPOSITION. 